nVidia GeForce 6800 GS Reference Card

The GeForce 6800 GT was a cracker. While nVidia wowed everybody with the 6800 Ultra it was the 6800 GT that most people bought, offering most of the bang without quite as much of the buck.

However, nVidia has decided that the 6800 GT has had its day. The reason? Well, ATI has been fighting back to compete with the GT. Firstly, there was the Radeon X800 XL, which followed the 6800 GT's blueprint of being a scaled back version of the top-end cards. But then ATI produced the X800 GTO. Unlike the Radeon X800GT we reviewed here, the GTO is a 12-pipline, six vertex shader card, running at 400MHz core, with 256MB of 980MHz GDDR3 with a full 256-bit memory interface. The GTO wasnâ€™t an officially road-mapped product but is the result of ATI having many failed versions of X800 and X850 parts; so much so that it was able to offer it as a unique product SKU. Over the last couple of months this has been doing damage to sales of nVidiaâ€™s 6800 series though the success of its 7800 series has deflected many from noticing this.
The time was ripe therefore for a response from nVidia and the result is the 6800 GS. Letâ€™s get this out of the way straight away. Despite having the same five vertex shaders and 256-bit memory interface, the GS has 12 pixel pipelines, four fewer than the 6800 GT. Yet, nVidia claims that the GS is faster than the GT. How is this possible? This is due to the GS possessing much greater clock speeds, with the reference card running at 425MHz core and 1GHz memory, compared to 350MHz, 1GHz for the standard GT. But clocks are much cheaper than pipelines and the 75MHz increase ensures that it can compete with the GT despite the reduced number of pipelines.

The reason nVidia is able to push the cards clock speeds is due to the fact that the GS is now based on nVidia NV42. This means that itâ€™s now a native PCI Express part built on a 110nm process, rather than the 130nm process of the GT with an AGP to PCI Express bridge.

Stock clock speeds havenâ€™t just increased however. One of the benefits of the reduced micron process is that thereâ€™s more headroom for overclocking and unusually for TrustedReviews weâ€™ve actually included some overclocked results to get a sense of what impact that has.